The present invention relates to a process for production of a synthetic paper substantially free of dusting trouble. In particular, it is concerned with a process for production of a synthetic paper having improved continuous printability, especially continuous offset printability.
Instead of cellulosic paper consisting of entangled cellulose fibers, various synthetic papers produced by paper-making synthetic resin films have been proposed. Among such synthetic papers there is one type of a synthetic paper comprising a paperlike layer consisting of a stretched film of resins with fillers incorporated therein. The synthetic paper of this type may be composed of either a single layer structure composed of only such a paperlike layer or a laminate structure composed on a substrate layer with the paperlike layer coated on at least one of the surfaces thereof (see, Japanese Pat. Publication No. 40794/71, of which U.S. Pat. Nos. 3,799,828 and 3,841,943 are the U.S. counterparts; and Japanese Pat. Publication No. 1782/74 of which U.S. Pat. No. 3,765,999 is the U.S. counterpart.
Good papery properties of such a synthetic paper comprising a paperlike layer consisting of a stretched film of resins with fillers incorporated therein can be contributed to the presence of microvoids developed around the filler particles throughout the film. The microvoids are uniformly distributed throughout the depth of the paperlike layer, and those present on or near the surface of the paperlike layer are open to the outside of the surfaces of the layer. The communication of the surface microvoids with the outside and the presence of exposed filler particles on the surface are due to the stretching of a film of a resin with the filler incorporated therein. These characteristics make it possible for this type of the synthetic paper to possess good quality of paper, printability or ink-receiving capacity and ink-drying property.